The Galaxy S6 didn’t have a microSD slot because Samsung was concerned about performance issues
Samsung fans didn’t like it when the company removed the microSD slot from its flagships last year. All previous Galaxy S series handsets supported external memory expansion so it was a big change for the company. A Samsung executive has revealed that concerns about performance issues were the primary reason for the microSD slot being booted from the Galaxy S6 and the Galaxy S6 edge.
Kyle Brown, the head of content, technology and launch management at Samsung, has said that the company was concerned that microSD support could slow down the performance of its 2015 flagship. The Galaxy S6 was the first Samsung smartphone to feature the company’s UFS 2.0 memory that’s almost three times faster than conventional eMMC 5.0 memory. The company was concerned about slow reading speeds for data stored on the memory card and felt that it would bog down the phone’s performance so it decided against supported microSD cards.
The Galaxy S7 and the Galaxy S7 edge build up nicely on the platform that the previous flagships built. Brown says that for the new handsets Samsung was able to work out a solution which enables users to get “the best of both worlds,” so not only do they get super-fast internal storage but they also get the ability to expand storage externally without feeling as if the phone is being bogged down.Source